Comparación de regímenes de variabilidad ambiental entre las localidades de Chome y Las Cruces, Chile central.
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Date
2024
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Universidad de Concepción
Abstract
Los ecosistemas costeros marinos son altamente dinámicos debido a la interacción de su topografía y geomorfología con diversos procesos físicos, ecológicos y biológicos. La variabilidad ambiental en estos ecosistemas ocurre a diversas escalas temporales, afectando la estructura y funcionamiento de las comunidades costeras. Este estudio compara los regímenes de variabilidad temporal, especialmente en las bandas de frecuencia sinóptica, diurna, semidiurna y de alta frecuencia, en temperatura y oxígeno disuelto en el agua de fondo de las localidades de Chome (36°46’S, 72°12’W) y Las Cruces (33°30’S, 71°37’W) en Chile central. Se utilizaron registros continuos de temperatura y oxígeno disuelto de 2017-2019 para Chome y de 2015-2017 para Las Cruces. Además, para contextualizar lo observado en estas localidades, se analizaron registros de las mismas variables en localidades cerca de interés: Coliumo y Algarrobo.
Las Cruces destacó como la localidad más cálida y con las mayores concentraciones promedio de oxígeno disuelto. En contraste, Chome y Algarrobo fueron las localidades más frías, presentando una mayor dispersión, particularmente en Chome. La variabilidad estacional fue dominante en las series de tiempo de temperatura y oxígeno disuelto en Chome y Las Cruces, especialmente en Chome, donde los mínimos registros para ambas variables durante primavera-verano se relacionaron con viento sur favorable a surgencia costera, alcanzando niveles de hipoxia en verano.
Descontando la señal estacional, la variabilidad a escala sinóptica fue la principal contribuyente a la variabilidad total en todas las localidades. Sin embargo, las bandas de variabilidad de corto periodo (bandas diurna, semidiurna y alta frecuencia) también tuvieron una contribución importante, especialmente en Las Cruces que presentó las mayores contribuciones de las bandas de corto periodo en temperatura (°C) y oxígeno disuelto (mg/L), concordando este último con las contribuciones de Chome, pero destacando para Chome la banda de variabilidad de alta frecuencia y para Las Cruces la banda diurna.
Chome y Las Cruces presentaron mayores similitudes en términos de la contribución de bandas de corto periodo, perfiles de variabilidad y valores absolutos de sus contribuciones en oxígeno disuelto. Sin embargo, Chome también mostró una alta similitud con Algarrobo en la variabilidad de alta frecuencia, perfil de variabilidad y valores absolutos en temperatura. Por el contrario, Coliumo fue la localidad con menor similitud respecto a las demás, destacándose por las menores contribuciones de las bandas de corto periodo y diferencias significativas en los valores absolutos de estas contribuciones.
Estos resultados subrayan la potencial importancia de la variabilidad ambiental de corto periodo en la costa de Chile central e indican que la similitud entre regímenes de variabilidad no depende necesariamente de la proximidad geográfica entre localidades. Factores locales como la topografía costera y patrones de viento, que pueden generar condiciones similares entre localidades distintas y, al mismo tiempo, diferencias marcadas entre localidades cercanas. Por lo tanto, para comprender la dinámica de sistemas costeros y su impacto en las comunidades biológicas, es necesario considerar análisis más detallados de la topografía costera y su interacción con procesos oceanográficos locales y regionales en diferentes escalas temporales.
Marine coastal ecosystems are highly dynamic due to the interaction of their topography and geomorphology with various physical, ecological, and biological processes. Environmental variability in these ecosystems occurs at different temporal scales, affecting the structure and functioning of coastal communities. This study compares temporal variability regimes, particularly in the synoptic, diurnal, semi-diurnal, and high frequency bands, in temperature and dissolved oxygen in the bottom waters of two sites in central Chile: Chome (36°46’S, 72°12’W) and Las Cruces (33°30’S, 71°37’W). Continuous records of temperature and dissolved oxygen were used for Chome (2017 2019) and Las Cruces (2015–2017). To contextualize the observations in these locations, records of the same variables were analyzed for two nearby sites: Coliumo and Algarrobo. Las Cruces was the warmest location, with the highest average oxygen concentrations. In contrast, Chome and Algarrobo were the coldest locations, exhibiting greater variability, particularly in Chome. Seasonal variability dominated the time series of temperature and dissolved oxygen in both Chome and Las Cruces, especially in Chome, where the minimum values of temperature and dissolved oxygen recorded during spring-summer were associated with southerly winds favorable to coastal upwelling, reaching hypoxic levels in summer. After discounting the seasonal signal, synoptic-scale variability was the main contributor to the total variability across all locations. However, short-period variability bands (diurnal, semi-diurnal, high frequency) also made significant contributions, especially in Las Cruces, which exhibited the highest contributions from short-period bands in both temperature and dissolved oxygen. In the case of dissolved oxygen, these contributions aligned with those of Chome, but Chome stood out in the high-frequency variability band, while Las Cruces was characterized by the diurnal band. Greater similarities were found between Chome and Las Cruces in terms of the contribution of short-period bands, variability profiles, and absolute values of their contributions in dissolved oxygen. However, Chome also showed high similarity with Algarrobo in high-frequency variability, variability profiles, and absolute temperatura values. Coliumo was the most dissimilar location, standing out for its lower contributions from short-period bands and significant differences in the absolute values of these contributions. These results underline the potential importance of short-period environmental variability along the central Chilean coast and indicate that similarities between variability regimes do not necessarily depend on the geographical proximity of locations. Local factors, such as coastal topography and wind patterns, which can create similar conditions between distant locations while generating marked differences between nearby ones. Therefore, understanding the dynamics of coastal systems and their impact on biological communities, it is necessary to conduct more detailed analyses of coastal topography and its interaction with local and regional oceanographic processes at different temporal scales.
Marine coastal ecosystems are highly dynamic due to the interaction of their topography and geomorphology with various physical, ecological, and biological processes. Environmental variability in these ecosystems occurs at different temporal scales, affecting the structure and functioning of coastal communities. This study compares temporal variability regimes, particularly in the synoptic, diurnal, semi-diurnal, and high frequency bands, in temperature and dissolved oxygen in the bottom waters of two sites in central Chile: Chome (36°46’S, 72°12’W) and Las Cruces (33°30’S, 71°37’W). Continuous records of temperature and dissolved oxygen were used for Chome (2017 2019) and Las Cruces (2015–2017). To contextualize the observations in these locations, records of the same variables were analyzed for two nearby sites: Coliumo and Algarrobo. Las Cruces was the warmest location, with the highest average oxygen concentrations. In contrast, Chome and Algarrobo were the coldest locations, exhibiting greater variability, particularly in Chome. Seasonal variability dominated the time series of temperature and dissolved oxygen in both Chome and Las Cruces, especially in Chome, where the minimum values of temperature and dissolved oxygen recorded during spring-summer were associated with southerly winds favorable to coastal upwelling, reaching hypoxic levels in summer. After discounting the seasonal signal, synoptic-scale variability was the main contributor to the total variability across all locations. However, short-period variability bands (diurnal, semi-diurnal, high frequency) also made significant contributions, especially in Las Cruces, which exhibited the highest contributions from short-period bands in both temperature and dissolved oxygen. In the case of dissolved oxygen, these contributions aligned with those of Chome, but Chome stood out in the high-frequency variability band, while Las Cruces was characterized by the diurnal band. Greater similarities were found between Chome and Las Cruces in terms of the contribution of short-period bands, variability profiles, and absolute values of their contributions in dissolved oxygen. However, Chome also showed high similarity with Algarrobo in high-frequency variability, variability profiles, and absolute temperatura values. Coliumo was the most dissimilar location, standing out for its lower contributions from short-period bands and significant differences in the absolute values of these contributions. These results underline the potential importance of short-period environmental variability along the central Chilean coast and indicate that similarities between variability regimes do not necessarily depend on the geographical proximity of locations. Local factors, such as coastal topography and wind patterns, which can create similar conditions between distant locations while generating marked differences between nearby ones. Therefore, understanding the dynamics of coastal systems and their impact on biological communities, it is necessary to conduct more detailed analyses of coastal topography and its interaction with local and regional oceanographic processes at different temporal scales.
Description
Tesis presentada para optar al título de Biólogo/a Marino/a.
Keywords
Ecología marina, Costas, Temperatura del océano, Oceanografía